Field of the Invention
The present invention relates to a damper device and an image forming apparatus including the damper device.
Description of the Related Art
In image forming apparatuses of the related art such as a copying machine, a printer, and a facsimile, an exterior cover serving as a moving part can be moved for the purposes of maintenance and replacement of inner mechanisms and a sheet jam clearing operation.
In recent image forming apparatuses, a damper device is installed for an exterior cover in order to improve operability of users and servicemen. Even when the user releases the user's hand from the exterior cover during an operation of opening or closing the exterior cover, the damper device prevents the exterior cover from opening under its own weight and making impact. Therefore, breakage of the exterior cover and components of the image forming apparatus and displacement of the positions of the components can be prevented from being caused by the impact.
As the damper device, a rack gear is meshed with a pinion gear that is engaged with a shaft protruding from a damper, and a damper function is exerted by applying load to the movement of the rack gear.
To properly exert the damper function, there is a need to prevent the gears from coming out of mesh (tooth skipping). Japanese Patent Laid-Open No. 2011-20516 discloses that a rack gear has flexibility and a contact area between the rack gear and that a pinion gear is bent in the radial direction of the pinion gear to prevent the gears from coming out of mesh.
In the structure described in Japanese Patent Laid-Open No. 2011-20516, the rack gear and the pinion gear are less likely to come out of mesh than when the rack gear does not have flexibility. However, even in this structure, the rack gear and the pinion gear sometimes come out of mesh. For example, great force is sometimes applied to the rack gear in a direction to separate the rack gear from the pinion gear. In such a case, there is a possibility that the gears come out of mesh and a proper damper function is not exerted.